Final answer:
The abstract base class for general purpose input streams is typically referred to as 'istream', but the base class for I/O operations including non-character input is 'std::ios_base' in C++.
Step-by-step explanation:
The name of the abstract base class for streams dealing with general purpose (non-character) input in many programming languages, like C++, is istream. However, when it comes to binary streams that are not character-specific, languages like C++ use a class called std::ios_base as the base class for I/O operations. General purpose input streams will inherit from std::ios_base or its derived classes, such as std::istream, which is used for input operations, and std::ostream, which is for output operations.